According to International Energy Agency data, from 1990 to 2008, the average energy usage per person increased by 10% while world population increased by 27%, resulting in a 39% increase in energy use worldwide. Growth in regional energy use over this period was especially high in emerging economies. Energy use in the Middle East increased by 170%, China by 146%, India by 91%, and Africa by 70%. In 2008, total worldwide energy consumption was 474 exajoules. ExxonMobil's 2012 “The Outlook for Energy: A View to 2040” states that global energy demand will be about 30% higher in 2040 compared to 2010, as economic output more than doubles and prosperity expands, with the need for energy to make electricity remaining the single biggest driver of demand.
In 2006, oil, coal and gas combined represented 88% of the world energy supply according to the National Energy Board of Canada. Both hydroelectric power and nuclear accounted for 6% each. Burning fossil fuels results in greenhouse gas emissions, which leads to climate change and an increase in extreme weather events. Combustion of fossil fuels also produces other air pollutants which contribute to smog and acid rain, which have adverse health impacts on humans as well as negative environmental impacts. Harvesting, processing, and distributing fossil fuels also create environmental concerns. Nuclear energy also has many unresolved environmental problems. Nuclear waste, power plant leaks, and catastrophic nuclear disasters are all negative consequences of nuclear power. The generation of hydroelectric power has environmental impacts as well. Hydroelectric dams and transmission lines have significant effects on water and biodiversity.
Currently, there are a number of alternative energy options in use or under development, but they make up a tiny proportion of world energy use due to the limitations currently associated with these technologies. Solar panels are currently very expensive to produce, and studies by the Electric Power Research Institute and elsewhere show that solar thermal technologies are far more expensive than coal. Though they emit no pollution while in use, there are environmental, health, and safety issues related to how they are manufactured, installed, and ultimately disposed of. The large amount of land required for utility-scale solar power plants poses an additional environmental problem. Solar power has limited performance—it works only during daylight hours, with peak production from 11 am to 1 pm on clear sunny days. There are also issues around site suitability, as solar panels require unobstructed, direct sunlight in a relatively cloud-free climate to operate at peak performance. Wind turbines also have high costs associated with construction and installation, though one of the biggest concerns associated with this form of energy is the potential impact on human health from Wind Turbine Syndrome caused by the low frequency noise emitted by the turbines. Bird and bat deaths as a result of collisions with the turbines is a major biological issue related to this form of alternative energy. Harnessing tidal energy is currently being explored as an alternative energy option, but tidal energy is only available twice a day which leads to low energy generation. Further, there is a high cost associated with the construction and installation of the large barrier dams necessary for energy capture, and there is a high environmental cost associated with harnessing this energy source as these dams restrict fish migration and cause silt build up which affects tidal basin ecosystems in negative ways.
There are many existing ideas for devices that extract energy from waves to provide electric power. To date none of these ideas has reached practical implementation. Existing ideas have proven to be uneconomical due either to high capital costs, or mechanical unreliability leading to short working life, or high maintenance costs. Most devices have two stages of conversion in which wave motion is converted to hydraulic or pneumatic power and then to electricity. Reliability problems can be traced to mechanical complexity of the devices in combination with the corrosive marine environment, or an inability to absorb higher than design wave conditions without damage to the mechanism.
A practical wave energy device would ideally feature low capital costs, minimal moving parts, high corrosion resistance, direct conversion from wave motion to electricity and a high tolerance for extreme wave conditions. Against this background, there is a need for solutions that will mitigate at least one of the above problems, particularly enabling the generation of electricity from motion of fluid such as ocean waves and river currents in an economical and/or efficient manner.